black welded steel (carbon?)

[tomb7us]

Is black welded steel safe to be heated to 500*F?

I don't know what grade it is heres the information i have:

schedule 40
OD 6.625"
ID 6.065"
wall thickness .280"
12" length

ASTEM A53, ASTM A733

Its under zero pressure.

Thanks,
Tom

 

[metengr]

The only effects of exposure to 500 deg F on this pipe material will be a drop in yield strength and ultimate tensile strength.

 

[vesselfab]

you mean a process operating temp of 500F?

personally, we refuse to use welded pipe on anything, but that is mostly because we don't want it in the shop to get mixed up with seamless. our standard is a-106-b which is seamless

 

[metengr]

I should add that this drop in mechanical properties is only during exposure at temperature. Once the pipe drops back to ambient temperature, it has no memory of the event.

 

[tomb7us]

Would it be okay maintained at 425 operating temp for 8 hours?

 

[metengr]

Yes, provided you understand that the material will have lower mechanical properties during this time.

 

[unclesyd]

Adding to the above posts we routinely clean our piping and process equipment made from A53, A106, and others by Pyrolysis. This process hold the parts at 700F for 4 to 6 hrs and then 900F for 1 hr. Some of the equipment has been cycled 100s' of times.